1. Field of Invention
The invention relates to a hybrid drive apparatus. The hybrid drive apparatus uses an engine and an electric motor as power sources. In particular, the hybrid drive apparatus uses a drive link structure for linking the power transmission systems of an engine and an electric motor.
2. Description of Related Art
A hybrid drive apparatus that uses an engine (i.e. an internal combustion engine) and an electric motor as power sources transmits the power from the two systems to a differential apparatus to adapt a variety of power train structures. Japanese Patent Application Laid-Open (JP-A No. 8-183347) discloses a drive apparatus having a structure in which the output from the engine and the output from the electric motor are transmitted to a differential apparatus with an optional gear ratio set for the engine and electric motor. In this drive apparatus, the engine and generator are placed on a first axis, the electric motor is placed on a second axis, a counter shaft is placed on a third axis, and the differential apparatus is placed on a fourth axis. The engine and generator are linked to the countershaft via a differential gear mechanism and the electric motor and differential apparatus are linked directly to the countershaft. Because the power of the two systems is transmitted to the vehicle wheels via the countershaft, a counter driven gear (the third gear 32 in the terminology of the aforementioned publication) is engaged with a drive gear, (the first gear 15 in the terminology of the aforementioned publication) is drive linked to the engine and a drive gear (the second gear 27 in the terminology of the aforementioned publication) is drive linked to the motor with the outputs from both the engine and the motor are input to the countershaft at optionally set gear ratios for each.
However, the demands on the vehicle vary when using the engine in a hybrid drive apparatus. For example, some vehicles may emphasize fuel consumption, while some vehicles emphasize acceleration. It is thus necessary to set the total gear ratio from the engine to the wheels higher for the fuel consumption emphasis, and to lower this ratio for the acceleration emphasis. In order to respond to these demands in the above hybrid drive apparatus, the diameters of the gear pairs linking the differential gear mechanism and the countershaft are altered so as to alter the total gear ratio on the engine side. However, the diameter of the gear pairs linking the electric motor and the countershaft is altered. Thus, the gear ratio on the motor side is affected. Moreover, as a result of the diameter of the gears being altered, the center distance between the countershaft on the third axis and the differential apparatus on the fourth axis is also changed which requires an alteration in the configuration of the casing.
Further, the engine side drive gear and the motor side drive gear mesh simultaneously with the counter driven gear. Also, gear face precision between the engine side drive gear and the counter driven gear and between the motor side drive gear and the counter driven gear must be provided simultaneously, which requires a great deal of man-hours.
Moreover, because the meshing degree (noise frequency) is the same, not only is a louder gear noise generated, but it is impossible to determine from the differences in the noise frequency whether the meshing portion causing the noise is between the counter driven gear and the engine drive gear or between the counter driven gear and the motor drive gear. Thus, it is impossible to implement measures which will reduce the noise.
The invention provides a hybrid drive apparatus capable of allowing the optional setting and further altering of total gear ratios on the engine side and on the motor side without the axial positions of the engine and generator, the electric motor, and the differential apparatus being altered. The invention separately provides an apparatus that simplifies the noise reduction measures when gear noise is generated in the hybrid drive apparatus.
In various exemplary embodiments, the invention is a hybrid drive apparatus including an engine, a generator, a differential gear mechanism linking the engine and the generator, an electric motor, and a differential apparatus, in which an output element of the differential gear mechanism is drive linked to the differential apparatus via a power transmission system on the side of the engine and generator, and the electric motor is drive linked to the differential apparatus via a power transmission system on the side of the electric motor, wherein the engine and the generator and the differential gear mechanism are placed on a common axis and output shafts of the electric motor and the differential apparatus are each placed on their own different axes which are parallel to the common axis, and the power transmission system on the side of the engine and generator and the power transmission system on the side of the electric motor are each formed from separate power transmission elements, and both are drive linked at the most downstream ends of their respective power transmission systems with the differential apparatus.
Specifically, the power transmission system on the side of the engine and generator is formed from power transmission elements that drive link the output element of the differential gear mechanism and a differential input gear of the differential apparatus, and wherein the power transmission system on the side of the electric motor is formed from power transmission elements that drive link a rotor shaft of the electric motor and the differential input gear.
In the above structure, the differential input gear of the differential apparatus includes a first and a second differential input gear; the power transmission system on the side of the engine and generator is formed from power transmission elements that drive link the output element of the differential gear mechanism and the first differential input gear; and the power transmission system on the side of the electric motor is formed from power transmission elements that drive link the rotor shaft of the electric motor and the second differential input gear.
In various exemplary embodiments, the hybrid drive apparatus includes an engine, a generator, a differential gear mechanism linking the engine and the generator, an electric motor, and a differential apparatus, in which the output element of the differential gear mechanism is drive linked to the differential apparatus via a power transmission system on the side of the engine and generator, and the electric motor is drive linked to the differential apparatus via a power transmission system on the side of the electric motor, wherein the engine and the generator and the differential gear mechanism are placed on a common axis and output shafts of the electric motor and the differential apparatus are each placed on their own different axes which are parallel to the common axis, and wherein the power transmission system on the side of the electric motor is drive linked to the differential apparatus via the power transmission system on the side of the engine and generator.
Specifically, the power transmission system on the side of the engine and generator is formed from power transmission elements that drive link the output element of the differential gear mechanism and the differential input gear of the differential apparatus, and wherein the power transmission system on the side of the electric motor is formed from power transmission elements that drive link the rotor shaft of the electric motor and the output element of the differential gear mechanism.
Specifically, the power transmission system on the side of the engine and generator is formed from a counter drive gear linked to the output element of the differential gear mechanism and power transmission elements that drive link this counter drive gear and the differential input gear, and wherein the power transmission system on the side of the electric motor is formed from an electric motor output gear fixed to the rotor shaft of the electric motor power transmission elements that drive link the electric motor output gear and the counter drive gear.
In the above structure, the power transmission system on the side of the engine and generator is formed from a first counter drive gear linked to the output element of the differential gear mechanism and power transmission elements that drive link the first counter drive gear and the differential input gear, and wherein the power transmission system on the side of the electric motor is formed from an electric motor output gear fixed to the rotor shaft of the electric motor power transmission elements that drive link the electric motor output gear and a second counter drive gear linked to the output element of the differential gear mechanism.
Moreover, in the above structure, the power transmission system on the side of the electric motor includes a sprocket fixed to the rotor shaft of the electric motor; a sprocket linked to the output element of the differential gear mechanism; and a chain entrained between the two sprockets.
In various exemplary embodiments, the hybrid drive apparatus includes an engine, a generator, a differential gear mechanism linking the engine and the generator, an electric motor, and a differential apparatus, in which the output element of the differential gear mechanism is drive linked to the differential apparatus via a power transmission system on the side of the engine and generator, and the electric motor is drive linked to the differential apparatus via a power transmission system on the side of the electric motor, wherein the engine and the generator and the differential gear mechanism are placed on a common axis and output shafts of the electric motor and the differential apparatus are each placed on their own different axes which are parallel to the common axis, and wherein the power transmission system on the side of the engine and generator are drive linked to the differential apparatus via the power transmission system on the side of the electric motor.
Specifically, the power transmission system on the side of the electric motor is formed from power transmission elements drive linking the rotor shaft of the electric motor and the differential input gear of the differential apparatus, and the power transmission system on the side of the engine and generator is formed from power transmission elements that drive link the output element of the differential gear mechanism and the rotor shaft of the electric motor.
More specifically, the power transmission system on the side of the electric motor is formed from the electric motor output gear fixed to the rotor shaft of the electric motor and power transmission elements drive linking the electric motor output gear and the differential input gear, and the power transmission system on the side of the engine and generator is formed from power transmission elements that drive link the output element of the differential gear mechanism and the electric motor output gear.
In the above structure, the power transmission system on the side of the electric motor is formed from the first electric motor output gear fixed to the rotor shaft of the electric motor and power transmission elements drive linking the first electric motor output gear and the differential input gear, and the power transmission system on the side of the engine and generator is formed from power transmission elements that drive link the output element of the differential gear mechanism and the second electric motor output gear that is fixed to the rotor shaft of the electric motor.
Moreover, in the above structure, the power transmission system on the side of the engine and generator includes a sprocket linked to the output element of the differential gear mechanism; a sprocket fixed to the rotor shaft of the electric motor; and a chain entrained between the two sprockets.
In various exemplary embodiments, the hybrid drive apparatus includes an engine, a generator, a differential gear mechanism linking the engine and the generator, and an electric motor, in which an output element of the differential gear mechanism is drive linked to the vehicle wheels via a power transmission system on the side of the engine and generator, and the electric motor is drive linked to the vehicle wheels via a power transmission system on the side of the electric motor, wherein the hybrid drive apparatus is provided with output shafts drive linking each of the power transmission systems and the vehicle wheels, and the power transmission system on the side of the engine and generator is formed from power transmission elements drive linking the output element of the differential gear mechanism and a first output gear fixed to an output shaft, and the power transmission system on the side of the electric motor is formed from power transmission elements drive linking the rotor shaft of the electric motor and a second output gear fixed to an output shaft.
In various exemplary embodiments, the hybrid drive apparatus includes an engine, a generator, a differential gear mechanism linking the engine and the generator, and an electric motor, in which an output element of the differential gear mechanism is drive linked to the vehicle wheels via a power transmission system on the side of the engine and generator, and the electric motor is drive linked to the vehicle wheels via a power transmission system on the side of the electric motor, wherein the power transmission system on the side of the engine and generator is formed from a first counter drive gear linked to an output element of the differential gear mechanism and power transmission elements drive linking the first counter drive gear and the vehicle wheels, the power transmission system on the side of the electric motor is formed from an electric motor output gear fixed to the rotor of the electric motor and power transmission elements drive linking the electric motor output gear and a second counter drive gear linked to an output element of the differential gear mechanism, and the power transmission system on the side of the electric motor is drive linked to the vehicle wheels via the power transmission system on the side of the engine and generator.
In various exemplary embodiments, the hybrid drive apparatus includes an engine, a generator, a differential gear mechanism linking the engine and the generator, and an electric motor, in which an output element of the differential gear mechanism is drive linked to the vehicle wheels via a power transmission system on the side of the engine and generator, and the electric motor is drive linked to the vehicle wheels via a power transmission system on the side of the electric motor, wherein the power transmission system on the side of the electric motor is formed from a first electric motor output gear fixed to the rotor of the electric motor and power transmission elements drive linking the first electric motor output gear and the vehicle wheels, the power transmission system on the side of the engine and generator is formed from power transmission elements drive linking the output element of the differential gear mechanism and a second electric motor output gear fixed to the rotor shaft of the electric motor, and the power transmission system on the side of the engine and generator is drive linked to the vehicle wheels via the power transmission system on the side of the electric motor.
In the structure of each exemplary aspect of the invention as mentioned above, an idler gear may constitute the power transmission element.
In the structure of each exemplary aspect of the invention as mentioned above, a counter reduction mechanism may constitute the power transmission element as a counter reduction gear mechanism.
In the structure of each exemplary aspect of the above invention as mentioned above, it is possible to constitute the power transmission element in one of the power transmission systems as an idle gear, and to constitute the power transmission element in the other power transmission system as a counter reduction gear mechanism.
In the structure of each exemplary aspect of the above invention as mentioned above, a coaxial reduction mechanism is inserted in at least one of the power transmission systems.